1. Field of the Invention
The invention relates to a process for the continuous chipless separation of identical individual rings from tubular workpieces.
2. Description of the Prior Art
Ring-shaped components are widespread in technology. In roller bearing technology, such components constitute a substantial portion, in terms of quantity, of the parts used. As is generally known, each roller bearing consists of at least two ring-shaped components, namely, the inner ring and the outer ring. These rings are produced in great numbers, for example, from tubular semifinished products of antifriction bearing steel. The division of tubular material into rings of equal size is thus a standard production step during the production of roller bearings. It is also a very important step, given the growing competition in the roller bearing industry. As efforts are made to achieve greater productivity and lower manufacturing costs, this production step assumes great significance. Especially during chip-producing separation, greater material expensive contributes to high costs.
A generic process for the chipless separation of identical individual rings from tubular workpieces is disclosed in German reference DE-OS 1602950. In this process, three cutting rollers with thread-shaped cutting edges are arranged around the workpiece to be processed. All three cutting rollers are driven in the same direction and pressed against the workpiece surface. The tubular workpiece rotates in the direction opposite to that in which the cutting rollers rotate and is thereby moved forward axially. The respective rotational positions of the three cutting rollers are such that the cutting contact with the workpiece occurs on an exactly shared cutting plane. The diameter of the cutting rollers increases, starting from the beginning and going toward the end, forming a narrowing channel. This device is not suitable for producing highly-accurate roller bearing rings, because the face regions of the separated rings are very rounded. Furthermore, the cutting edges of the cutting rollers wear out rapidly, because antifriction bearing steel has especially high deformation resistance; no measures to reduce this deformation resistance are indicated.
Another process for dividing tubular material is known from German reference DE-PS 10 13 487. In this process, a working head revolves around the tube to be divided. The working head has die holders arranged peripherally on a cross-sectional plane as well as cutting rollers mounted detachably in these holders. The cutting, rollers have cutting edges with substantially radial flanks, which can be brought to rest on the face of the tube to be divided during the dividing process. This process permits only discontinuous separation of individual tube segments. The device is not suitable for continuously separating identical rings from tubular material in short cycles.